DIY Concrete & Mortar Calculator｜Estimate Cement, Sand, and Gravel Bags

Planning a DIY project like a small patio slab, setting fence posts, or a masonry repair? This tool helps you accurately calculate the amount of cement, sand, and gravel you'll need. Instantly get a shopping list to avoid over-buying or running out of materials mid-project.

💡 Tool Overview

This calculator simplifies material estimation for your next construction or repair task. Simply input your project's dimensions to determine the required supplies.

• Dual-Mode Calculation: Choose between "Concrete" for structural work (e.g., slabs, foundations) or "Mortar" for bonding bricks or blocks.
• Volume-Based Estimation: Automatically calculates the total volume of material needed in liters based on the dimensions you provide.
• Automatic Bag Count: Instantly converts the required volume into the number of bags of cement (25kg), sand (20kg), and gravel (20kg) you'll need to purchase.
• One-Click Shopping List: Generates a clean, copyable shopping list summarizing all your required materials, making your trip to the hardware store quick and easy.

🧐 Frequently Asked Questions

Q. What is the difference between concrete and mortar?

A. The main difference is the aggregate. Concrete is a mix of cement, sand, and a coarse aggregate like gravel, which gives it high compressive strength suitable for structural applications. Mortar is a mix of just cement and sand, used as a binding agent to hold bricks, stones, or blocks together. This calculator adjusts its material recommendations based on your selection.

Q. Are these calculations exact?

A. These calculations provide a close estimate based on standard material densities and common mix ratios. However, we recommend purchasing slightly more (e.g., an extra 5-10%) to account for spills, uneven ground, or minor measurement inaccuracies. The calculation assumes standard bag sizes of 25kg for cement and 20kg for sand and gravel.

📚 Pro-Tips for DIY Concrete Mixing

A common and reliable mix ratio for general-purpose concrete is 1:2:4—one part cement, two parts sand, and four parts coarse aggregate (gravel). This calculator uses conversion factors that closely align with this trusted ratio, ensuring a strong and durable final product for most DIY applications.

When mixing, always add water gradually. The goal is a workable, plastic-like consistency similar to thick oatmeal. Too much water will weaken the concrete, while too little will make it difficult to pour and finish. Start with about half the estimated water and add more until you reach the desired consistency.